Purenex 2C-2GAC-2S-1I 7-Filter 1-Year Replacement Kit for 5-Stage Reverse Osmosis 2 of Granular Activated Carbon filters (GAC) 5 Micron 2 of Block Activated Carbon filters 5 Micron 2 of Melt-blown Polypropylene Sediment filters 5 Micron 1 of Inline Pre/Post Membrane filters